Part 4 – Loss of Biodiversity (25 MCQs)

Q1. Which of the following is the biggest cause of biodiversity loss worldwide?

a) Overexploitation
b) Habitat loss and fragmentation
c) Alien species invasion
d) Co-extinction

Answer: b) Habitat loss and fragmentation

Explanation:

(a) Incorrect → Important but not the largest cause.
(b) Correct → Deforestation, urbanization, agriculture cause maximum biodiversity loss.
(c) Incorrect → Alien invasions are secondary causes.
(d) Incorrect → Co-extinction is a consequence, not the primary cause.

Q2. Which of the following activities results in habitat loss?

a) Slash-and-burn agriculture
b) Urbanization
c) Deforestation
d) All of the above

Answer: d) All of the above

Explanation:

(a) Correct → Shifting cultivation destroys habitats.
(b) Correct → Expanding cities reduce natural ecosystems.
(c) Correct → Logging destroys forests.
(d) Correct → All contribute.

Q3. Which of the following is NOT a cause of biodiversity loss?

a) Overexploitation
b) Invasive species
c) Conservation reserves
d) Habitat fragmentation

Answer: c) Conservation reserves

Explanation:

(a) Correct → Overexploitation reduces biodiversity.
(b) Correct → Alien invasions threaten species.
(c) Correct answer → Reserves conserve biodiversity.
(d) Correct → Fragmentation isolates species.

Q4. Which alien fish introduced in Indian rivers threatens native catfish?

a) Catla
b) Gambusia
c) Clarias gariepinus (African catfish)
d) Rohu

Answer: c) Clarias gariepinus (African catfish)

Explanation:

(a) Incorrect → Catla is a native carp.
(b) Incorrect → Gambusia eats mosquito larvae, but not catfish.
(c) Correct → African catfish competes with native catfish.
(d) Incorrect → Rohu is native.

Q5. Which alien species was introduced in India to control mosquitoes?

a) Gambusia
b) Nile perch
c) Parthenium
d) Clarias gariepinus

Answer: a) Gambusia

Explanation:

(a) Correct → Gambusia fish feeds on mosquito larvae.
(b) Incorrect → Nile perch introduced in Lake Victoria.
(c) Incorrect → Parthenium = invasive weed.
(d) Incorrect → Clarias gariepinus = invasive catfish.

Q6. The Nile perch introduced in Lake Victoria caused extinction of:

a) Cichlid fish species
b) Catfish species
c) Whale populations
d) Amphibians

Answer: a) Cichlid fish species

Explanation:

(a) Correct → >200 cichlid species extinct due to Nile perch.
(b) Incorrect → Not catfish.
(c) Incorrect → Whales not present in lake.
(d) Incorrect → Amphibians not impacted.

Q7. Alien invasive plant species Parthenium hysterophorus is also called:

a) Water hyacinth
b) Congress grass
c) African catfish
d) Lantana

Answer: b) Congress grass

Explanation:

(a) Incorrect → Eichhornia = water hyacinth.
(b) Correct → Parthenium = Congress grass.
(c) Incorrect → Catfish is an animal.
(d) Incorrect → Lantana is another invasive plant.

Q8. Which alien invasive plant is called “Terror of Bengal”?

a) Parthenium
b) Water hyacinth
c) Lantana
d) Ipomoea

Answer: b) Water hyacinth

Explanation:

(a) Incorrect → Congress grass, not “terror.”
(b) Correct → Eichhornia crassipes = “Terror of Bengal.”
(c) Incorrect → Lantana = invasive shrub.
(d) Incorrect → Ipomoea is different.

Q9. Co-extinction refers to:

a) Extinction of prey leading to predator loss
b) Extinction of host causing extinction of parasite
c) Extinction of one species leading to loss of dependent species
d) All of the above

Answer: d) All of the above

Explanation:

(a) Correct → Predator–prey dependency.
(b) Correct → Host–parasite dependency.
(c) Correct → General definition.
(d) Correct → All valid.

Q10. Example of co-extinction in biodiversity loss is:

a) Cichlid loss in Lake Victoria
b) Passenger pigeon extinction
c) Extinction of a parasite with its host
d) Overhunting of tigers

Answer: c) Extinction of a parasite with its host

Explanation:

(a) Incorrect → Alien invasion, not co-extinction.
(b) Incorrect → Overexploitation, not co-extinction.
(c) Correct → Host–parasite example of co-extinction.
(d) Incorrect → Overhunting.

Q11. Which of the following is an example of overexploitation?

a) Extinction of passenger pigeon
b) Hunting of Steller’s sea cow
c) Overfishing in oceans
d) All of these

Answer: d) All of these

Explanation:

(a) Correct → Passenger pigeon wiped out by hunting.
(b) Correct → Sea cow hunted to extinction.
(c) Correct → Overfishing depleted species.
(d) Correct → All are examples.

Q12. The IUCN Red List estimates that at least _____ species face the threat of extinction.

a) 15,000
b) 30,000
c) 50,000
d) 70,000

Answer: c) 50,000

Explanation:

(a) Incorrect → Too low.
(b) Incorrect → Not NCERT value.
(c) Correct → 50,000 species threatened.
(d) Incorrect → Too high.

Q13. Which group has the maximum number of threatened species?

a) Mammals
b) Amphibians
c) Birds
d) Plants

Answer: d) Plants

Explanation:

(a) Incorrect → Mammals fewer than plants.
(b) Incorrect → Amphibians many but not maximum.
(c) Incorrect → Birds fewer than plants.
(d) Correct → Plants top the threatened list.

Q14. Which is NOT an example of overexploitation leading to extinction?

a) Passenger pigeon
b) Steller’s sea cow
c) Cichlid fishes of Lake Victoria
d) Dodo bird

Answer: c) Cichlid fishes of Lake Victoria

Explanation:

(a) Correct → Overexploited by humans.
(b) Correct → Sea cow overhunted.
(c) Correct answer → Cichlids extinct due to alien Nile perch, not overexploitation.
(d) Correct → Dodo hunted to extinction.

Q15. Which of the following human activities causes habitat fragmentation?

a) Deforestation
b) Road construction
c) Building dams
d) All of these

Answer: d) All of these

Explanation:

(a) Correct → Clearing forests fragments habitats.
(b) Correct → Roads cut through forests.
(c) Correct → Dams break river ecosystems.
(d) Correct → All are causes.

Q16. Which invasive alien species has choked Indian water bodies?

a) Lantana
b) Parthenium
c) Eichhornia
d) Opuntia

Answer: c) Eichhornia

Explanation:

(a) Incorrect → Lantana = invasive shrub.
(b) Incorrect → Congress grass, not aquatic.
(c) Correct → Eichhornia crassipes (water hyacinth).
(d) Incorrect → Opuntia = cactus invasive in dry areas.

Q17. What is the main reason why alien species become invasive?

a) They lack natural predators in new habitat
b) They are genetically weaker
c) They are less adaptable
d) They reproduce very slowly

Answer: a) They lack natural predators in new habitat

Explanation:

(a) Correct → Uncontrolled growth due to no predators.
(b) Incorrect → They are often stronger.
(c) Incorrect → They are highly adaptable.
(d) Incorrect → They reproduce fast, not slow.

Q18. Which of the following is an example of species extinction due to overhunting?

a) Passenger pigeon
b) Cichlid fishes
c) Water hyacinth
d) Parthenium

Answer: a) Passenger pigeon

Explanation:

(a) Correct → Extinct due to hunting.
(b) Incorrect → Lost due to alien invasion.
(c) Incorrect → Invasive weed, not extinction.
(d) Incorrect → Invasive weed.

Q19. Which term describes extinction of one species leading to the extinction of another dependent species?

a) Overexploitation
b) Co-extinction
c) Habitat fragmentation
d) Genetic drift

Answer: b) Co-extinction

Explanation:

(a) Incorrect → Different cause.
(b) Correct → Loss of dependent species.
(c) Incorrect → Fragmentation is different.
(d) Incorrect → Genetic drift relates to alleles.

Q20. Which invasive alien species caused damage to forests in India?

a) Parthenium
b) Lantana
c) Eichhornia
d) All of these

Answer: b) Lantana

Explanation:

(a) Incorrect → Parthenium = agricultural weed.
(b) Correct → Lantana spread in Indian forests.
(c) Incorrect → Eichhornia affects water bodies.
(d) Incorrect → Not all equally affect forests.

Q21. Which is an indirect cause of biodiversity loss?

a) Deforestation
b) Urbanization
c) Pollution
d) Global climate change

Answer: d) Global climate change

Explanation:

(a) Incorrect → Direct cause.
(b) Incorrect → Direct cause.
(c) Incorrect → Direct cause.
(d) Correct → Climate change indirectly affects species.

Q22. Which type of biodiversity loss occurs when a forest is broken into smaller patches?

a) Overexploitation
b) Habitat fragmentation
c) Alien invasion
d) Co-extinction

Answer: b) Habitat fragmentation

Explanation:

(a) Incorrect → Hunting, not fragmentation.
(b) Correct → Forest split into patches.
(c) Incorrect → Alien invasion is separate.
(d) Incorrect → Not co-extinction.

Q23. Which of the following is a global consequence of biodiversity loss?

a) Reduced ecosystem services
b) Climate imbalance
c) Loss of food resources
d) All of these

Answer: d) All of these

Explanation:

(a) Correct → Fewer services available.
(b) Correct → Disturbed climate cycles.
(c) Correct → Food shortages.
(d) Correct → All consequences.

Q24. Which invasive alien cactus damaged rangelands in India before being controlled by a moth?

a) Parthenium
b) Eichhornia
c) Lantana
d) Opuntia

Answer: d) Opuntia

Explanation:

(a) Incorrect → Parthenium is a weed.
(b) Incorrect → Eichhornia is aquatic.
(c) Incorrect → Lantana is a shrub.
(d) Correct → Opuntia controlled by cochineal insect.

Q25. Which of the following is a direct driver of biodiversity loss?

a) Climate change
b) Habitat destruction
c) Pollution
d) All of the above

Answer: d) All of the above

Explanation:

(a) Correct → Climate change directly impacts biodiversity.
(b) Correct → Habitat destruction is primary cause.
(c) Correct → Pollution directly damages ecosystems.
(d) Correct → All are direct drivers.

Biodiversity Class 12 MCQs, NCERT Biology Chapter 13, CBSE Class 12 Biology MCQs, NEET UG Biology preparation, Biodiversity hotspots MCQs, Endangered species Class 12, Biodiversity conservation notes, Red Data Book MCQs, biodiversity and its conservation class 12 mcqs with answers, biodiversity conservation neet important questions, class 12 biology chapter 13 mcqs for board exam, ncert based biodiversity questions for neet ug, biodiversity hotspots class 12 important mcqs, endangered organisms and extinction mcqs for neet, red data book class 12 biology questions, sacred groves and biosphere reserves mcqs

Part 4 – Loss of Biodiversity (25 MCQs)